Muscle Types Flashcards
Muscle types
Skeletal, cardiac and visceral (smooth)
Muscle functions
- each muscle type undergoes the process of shortening or contraction
- contraction process causes movement of body parts and organs
Skeletal muscle
Location
Each end is attached to a different bone at its origin and insertion
Skeletal muscle
Function
- moves the bones or a body part during the contraction process
- since contraction is controlled by conscious thought, the muscle action is said to be voluntary
Skeletal muscle
Tissue structure
Components
-composed of bundles of cells surrounded by connective tissue
Skeletal muscle
Tissue structure
Tissue arrangement
-fascicles, endomysium, perimysium, epimysium, tendon, aponeurosis
Fascicles
Band or bundle of nerve or muscle fibers
Endomysium
(Deep layer) surrounds muscle fibers
Perimysium
(Middle layer) surrounds fasciculi
Epimysium
(Superficial layer) surrounds groups of fasciculi; surrounds muscle
Tendon
(Band or chord) extensions of fibrous tissue beyond muscle cells
-forms string structure to anchor muscle to bone or other muscle
Aponeurosis
Wide ban of fibrous tissue between some muscles
Ie. scalp and abdomen
Skeletal muscle
Cell structure
- fibers (cells): very long and cylindrical; extends the length of muscle fasiculi, which in some cases is the length of the muscle
- nuclei: multiple; peripherally located
- striations: yes
Cardiac muscle
Location
- found in the walls of the heart
- composes most of the structure of the heart
Cardiac muscle
Function
- main action is to move blood through blood vessels as it contracts
- -this ensures delivery of blood to all body cells and tissues
- process of contraction is involuntary
- -heart contraction is controlled by the pacemaker tissue and by the autonomic nervous system
Cardiac muscle
Tissue structure
- cells are branched and connect to each other by intercalated disks
- little connective tissue between the cells
- cells form large units that can contract together
Myocardium
Muscle of the heart
Cardiac muscle
Cell structure
- fibers: cylindrical and branched
- nucleus: single; centrally located
- striations: yes
- intercalated disks: joins cells to one another
Visceral (smooth) muscle
Location
Located in the walls of most internal organs
Visceral (smooth) muscle
Functions
- contraction controls the actions of the internal organs such as the stomach, intestines, respiratory tubes and reproductive organs
- substances are moved through these organs as the muscle in the wall contracts
- involuntary and controlled by autonomic nervous system and hormones
Visceral (smooth) muscle
Tissue structure
- arranged in large sheets with many gap junctions between cells (unitary smooth muscle: contracts as a whole unit)
- fewer gap junctions and cells (or groups of cells) tend to act as independent units (multi unit smooth muscle)
Visceral (smooth) muscle
Cell structure
- fibers: spindle shaped
- nucleus: single; centrally located
- smooth appearance, no striations
Rectus abdominus
Origin: pubic crest, symphysis pubis
Insertion: inferior ribs, xiphoid process
Action: flexes vertebral column
External oblique
Internal oblique
Transverse abdominus
Compress abdomen and rotate trunk
Coccygeus
Elevates pelvic floor
Levator ani
Elevates anus
Pectoralis major
Rotates and adducts arm
Deltoid
Origin: clavicle, acromion process, spine of scapula
Insertion: deltoid tuberosity of humerus
Action: abducts, flexes, rotates arm
Teres major
Origin: lateral border of scapula
Insertion: crest of lesser tubercule of humerus
Action: extends adducts rotates stem medially
Infraspinatus
Extends rotates arm laterally
Biceps brachii
Origin: supraglenoid tubercle, coronoid process of scapula
Insertion: radial tuberosity
Action: main forearm flexor
Brachialis
Brachoradialis
Flex forearm
Pronator teres
Pronates hand
Flexor Capri radialis
Flexes adducts hand
Flexor Capri ulnaris
Flexes adducts hand
Palmaris longus
Flexes hand
Flexor digitorum
Flexes fingers and hand
Flexor pollicis
Flexes thumb
Triceps brachii
Origin: infraglenoid tuberosity of scapula, lateral and posterior surface of humerus
Insertion: olecranon process of ulna
Action: main forearm extensor
Extensor digitorum
Extend fingers and hand
Extensor Capri ulnaris
Extends adducts hand
Extensor Capri radialis
Extends adducts hand
Extensor pollicis
Origin: posterior radius and ulna, interosseus membrane
Insertion: proximal an distal phalanges of thumb
Action: extend thumb
